1. Field of the Invention
This disclosure relates to a memory device and its method of fabrication, and more particularly, to a memory device and its method of fabrication.
2. Description of the Related Art
There are several types of conventional semiconductor memory devices. For example, read only memory (ROM) type devices are non-volatile and thus stored data are retained even when their power supply is terminated. Random access memory (RAM) devices are volatile, and thus their stored data are erased when their power supply is terminated.
A flash memory device is an example of a non-volatile memory device in which the stored data can be electrically erased or written (i.e., programmable). In practice, flash memory devices are widely used in computers and memory cards because they can be erased in a single process, and are electrically programmable. However, flash memory devices should be more highly integrated with higher capacity to adapt them in commercial memory devices. Accordingly, the area of transistors included in a memory cell array and a peripheral circuit must be reduced in flash memory devices.